1. Field of the Invention
The present invention relates to a printing apparatus. Particularly, the present invention relates to a printing apparatus, which can selectively connect various extension boards to extend functions.
2. Description of the Related Art
Conventionally, a printing apparatus, which incorporates a CPU specialized to specific function processing independently of a CPU required to control the overall apparatus so as to extend functions, has been proposed.
For example, a controller board originally equipped in a printer has predetermined functions. Also, a printer, which implements operations as that having more advanced functions than the predetermined functions by mounting an extension CPU board, is available (see Japanese Patent Laid-Open No. 2007-210144). In the printer in which a CPU on the extension board and that on the controller board execute parallel processing to extend functions in this way, since the plurality of CPUs are concurrently driven, power consumption increases considerably.
On the other hand, nowadays, a requirement to reduce power consumption of an apparatus with consideration for environments has been increasing.
For this reason, in some printers, when a printer has not been used for a long time period, power is supplied to only minimum required functional blocks required to receive data from a host and to attain transition to a normal operation mode, and power supply and clock supply to unnecessary functional blocks are stopped, thereby reducing power consumption.
Also, the following proposal has been made (see Japanese Patent Laid-Open No. 2005-225175). That is, in this proposal, power consumption reduction execution methods are switched depending on whether or not an additional functional block connected to an extension slot is compatible with a power-saving mode, so as to reduce power consumption in the aforementioned printer which can extend functions using extension slots.
However, Japanese Patent Laid-Open No. 2005-225175 does not consider to entrust control on the extension board side and to stop power supply to the controller board itself, so as to attain a further reduction of power consumption in a power-saving mode.
An inkjet printer performs printing by supplying an ink stored in an ink supply source such as an ink cartridge to a printhead via an ink supply channel, and discharging ink droplets from nozzles of the printhead onto a print sheet. For this reason, when ink discharge operations from the nozzles of the printhead have not been performed for a long time period, volatile components are vaporized from the nozzles, thus causing troubles such as high viscosity of residual ink and entry of air bubbles from the nozzles to the interior.
Hence, an ink suction mechanism required to suck and externally eject inks from the nozzles of the printhead is arranged in the inkjet printer, so as to suck inks from the respective nozzles of the printhead, thus providing a cleaning mechanism of the printhead to always maintain an appropriate printable state. With this mechanism, processing for recovering the performance of the printhead to a given level (head recovery processing) is periodically executed. Such head recovery processing has to be executed every time a predetermined time period elapses.
However, in the inkjet printer which can extend functions using the extension boards, as described above, a timer is provided to the controller board in consideration of a case in which no function is extended, and the head recovery processing is executed in response to an interrupt signal, which is output after an elapse of a prescribed time period. Therefore, the CPU on the controller board has to be always ready to receive the interrupt signal from the timer. Even when a CPU and timer are equipped on the extension board, an arrangement that entrusts the control on the extension board side, and stops power supply to the controller board cannot be adopted. For this reason, the controller board cannot attain a power-saving mode, and does not suffice to reduce power consumption.